Abrupt

I live in greater Chicago (Illinois), and have frequently ridden the “L” into the city. (The “L” or “El” train is Chicago’s subway/underground. Though actually a significant portion is elevated above the city, hence the “El”.) I can confirm the abrupt stops. And when you’re attempting to travel with a load of books/massage equipment, it’s that much more of a pain in the butt. Though it wasn’t so bad when my extra equipment was all pillows.

Something about your style is really good, but i can't put my finger on it

Try Taking the District Of Columbia Metro system, they go SUPER fast and as such stop Abruptly and Depart the same way with a jolt backwards.

The rail system where I live is very gentle. You can't tell it is moving, or even that it exists at all.

Hmmm. I've been on trains in St. Louis, San Francisco, Atlanta, and Washington DC in the U.S., and London and Paris overseas, and none of them seemed particularly different with respect to stopping and starting that I can recall.

As a New Yorker who uses the subway all the time, this is true. There's this whole thing called subway legs where you do a certain stance in order to not fall over or get jerked around.